


Efficacy

by GuyOfShy



Series: Remontant [14]
Category: Final Fantasy XIII, Final Fantasy XIII Series
Genre: Blow Jobs, Cock Worship, Come Swallowing, Explicit Sexual Content, F/F, Farroncest - Freeform, Fluff and Smut, Futanari, Oral Sex, Plot What Plot/Porn Without Plot, Shameless Smut, Sibling Incest, Sibling Love, Sister/Sister Incest
Language: English
Status: Completed
Published: 2020-10-31
Updated: 2020-10-31
Packaged: 2021-03-09 03:49:13
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,323
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27307999
Author URL: https://archiveofourown.org/users/GuyOfShy/pseuds/GuyOfShy
Summary: Lightning blows Serah and blows her mind while she’s at it.
Relationships: Serah Farron/Lightning
Series: Remontant [14]
Series URL: https://archiveofourown.org/series/518764
Comments: 2
Kudos: 31





	Efficacy

“You’re starting to get really, _really_ good at this you know, Lightning. Fuck…”

‘ _Starting?_ ’ Lightning’s frown asked, falling for the challenge.

She pushed Serah's cock down deeper, with a little effort, until her lips touched her lap. The sudden plunge earned a breathy moan from Serah who craned her head back and curled her toes in her white kneesocks, gazing back down to find Lightning looking complacently at her. Finally she rose up and off, strings of spit trailing to Serah’s head. Serah gripped the edge of the mattress as she watched Lightning lick those up and resume stroking while she caught her breath.

“Starting?” She asked, grinning at her sister who was recovering as well. “Nice try, but your cute little moans are all I need to hear to know that I’m damn good at making you cum.”

“You know, you’re right. You always try so hard for me, you slut. Sorry- Sergeant Slut.”

“Anything for my little sister,” Lightning said oh-so-innocently, smiling like a cherub as she smooched the crown of Serah’s cock.

“God… Keep doing that Light.” Serah shivered, loving the touch and sound of Lightning’s lips, watching kiss after kiss planted along her shaft. Lightning offered her hand; the brush of their fingers filled Serah with an entirely different sense of joy, like warm waves cresting above the water. Serah ran her thumb over Lightning’s knuckles and Lightning squeezed back, following her orders obediently while brimming with confidence, always in an effort to make Serah ask more of her - to crack the whip on her cock-craving bitch - and Serah did by gripping Lightning’s hair and leading her lips around her cock where she desired. “I’m starting to think that you enjoy this more than I do.”

“You think?” Lightning mused before dragging her tongue from Serah’s base to her tip, punctuating with a touch of her lips.

“I think that you might even be worthy of a promotion from sergeant. Impress me enough and maybe you’ll earn it.” Serah leaned forward and pet her little lapdog’s head, ready to resume and put her to work. But before that, Lightning’s eyes and head drifted downward to show some love to Serah’s sack.

“What kind of bonuses come with the position?” Light asked as Serah’s spittle-covered cock rested on her face, all while she kissed and smooched and sucked.

“The bonus _is_ the position: on your knees and ready to please. Something you’re already well acquainted with,” Serah sang, adoring her sister's guilty grin. “You look good with my cock on your face.”

“I’d look even better with your cum on my face,” Lightning breathed, desperately.

“You’d just love that, wouldn’t you?”

“Mhm,” she mumbled with her mouth occupied, using her free hand to slowly stroke Serah’s base, building a source of pleasure from the bottom and letting it float upwards. Serah exhaled loudly, morphing into a quiet whine on the way out.

Lightning, letting her actions speak for her, kissed Serah’s tip and slid back down her length, swirling and circling her tongue swiftly around her head. That always felt so fucking good; Serah bit her lip, always impressed by her sister’s technique. Lightning never wasted a movement nor a moment in pleasing her, determined and relentless in treating her as best as she could. Serah never could last too long receiving that kind of devoted service, and currently Lightning’s dancing tongue brought her to the edge of climax. Her hips moved in little thrusts, and Lightning bobbed to her rhythm while looking curiously up at Serah, wondering where she was wanting to relieve her quivering cock.

On her face as she suggested? Tongue? Or down her throat? Serah had been hazily contemplating how to finish but she thought less about it and more about Light’s cool blue eyes staring her down. No matter the activity - fingering, fucking, flirting - Lightning always kept her eyes on Serah. Sometimes Serah thought it to be the selfless instinct to care for her sister - a deeply incestuous idea that only turned her on - and sometimes knew it must have been the selfish desire to watch her lover with lust, but amidst all the pleasure Lightning was inflicting on her, as tempting as her tongue or her face were, Serah’s mind obsessed over that moment where Lightning descended to the base of her cock.

Serah ran her fingers through Lightning’s hair, letting her catch her breath before turning her gentle hold tight as she pushed Lightning’s head down between her thighs. Serah whimpered and melted in her sister’s mouth as the tightening knot of pleasure at her root unfurled with a blissful force. Lightning swallowed her cock and cum until quietly gagging and Serah immediately let her go. Lightning relented halfway back, just for a moment of respite, before dutifully diving back down, defying Serah’s expectations.

“Fuck, Light, you’re so good…”

Serah trembled and covered her mouth as she came, fighting back the curses behind her lips as warm globs erupted into Lightning’s. She felt Lightning’s throat swallow around her cock, coaxing every drop out with ease. Once Serah’s hips slowed with a hot and heavy sigh, Lightning eyed Serah with a lusty stare as she slowly backed up and off, leaving a healthy gloss of spit behind. She swallowed the mix of saliva and semen that remained and took an equally deep breath, grinning at Serah whose face was flushed red.

“Like I said,” Lightning smirked as she kissed the last drops of cum away, “those cute as hell moans are all I need to hear.”

“You’re the best,” Serah said in a breath, her face and chest still warm. Completely satisfied emotionally and physically, and still Lightning continued to please; Lightning rose off her knees and pushed Serah back onto the bed by her shoulders, lying on top of her and kissing her neck.

“I assume that I’ve earned that promotion from, what was it? Sergeant Slut?” Lightning asked, waiting for Serah to sing her praises. Serah turned over to face her, but Lightning simply moved to her lips and continued kissing. Serah gladly returned fire until Lightning wanted her answer and backed off to let her say it.

“...What rank is above Sergeant?”

Lightning scoffed, and then chuckled, “Lieutenant.” She rose up to look at the embarrassment on Serah’s face, who had been so confident until having to ask that so cluelessly. But Serah was still catching her breath, and in that soberingly awkward moment she had only just calmed her heart and cleared her head. Lieutenant?

“I don’t know,” she laughed. “I can’t think of anything. Until I think of something better, you're just Lieutenant Lightning. Or Sergeant Slut, if you’d prefer.”

Lightning laughed too and laid down next to her, wrapping her ponytail around her finger. “You can think it over while you clean up in the shower.”

“Care to join me?” Serah tried with an honest look.

“Is that an order?”

“No. Up to you.”

“Only if you promise to behave.”

“If you hadn’t just blown me and blown my mind while you were at it, I would normally make no such promises, but I don’t think I have anything left in me after that. Also, bold words from Miss 'hey-sis-want-me-to-blow-you?'.”

Lightning smiled at being caught and called out. “You start the water, and I’ll grab the towels.”

As Lightning stood, Serah marvelled at her body for just a moment: beauty that Serah would be sure to worship in return sometime soon. But before Lightning got too far Serah sat up and grabbed her hand. She pulled her down for a kiss, slow and sweet. “Thanks Light. That was amazing.”

“It was my pleasure, trust me.”

Serah grinned at the perfect opportunity to call Lightning a slut again but sputtered into a laugh before she even finished the word. She apologized but Lightning just rolled her eyes and walked to the closet.

“Love you too Serah.”

“Love you more.”

**Author's Note:**

> Not super duper pleased about this one, but I really don't feel like working on it anymore, so here you go. Happy Halloween.


End file.
